The present invention relates to fast-acting motorized valves with axis-symmetrical saddles and turnable (cylindrical, conical, and preferably spherical) valve bodies. Such valves are designed for accurate regulation of flows of arbitrary flow media based on liquids and/or gasses and for closing/opening of vacuum lines.
Valves with turnable valve bodies and manual drives for their turning are known. Such valves are widely used in household, laboratory and industrial distribution networks for gas and water supply, for closing and opening of corresponding pipelines and regulation of gas and liquid supplies in the cases when an operator can manually turn the valve body, and fast activation of the valve and angular accuracy of positioning of the valve body in the saddle are not critical parameters.
However, in energy generating industries, in particular in thermal and nuclear power plants, in chemical industry and even in food industry, as well as for oil and gas pipelines, it is necessary to provide reliable and fast-acting valves, in which a starting torque significantly exceeds the manual possibilities of an operator, and in which it is necessary to provide accuracy of positioning of the valve bodies relative to the seats, and of the geometric axes of inlet and outlet pipes, at the level of several angular seconds. There is also a need to provide high-accuracy microvalves, in which a starting torque necessary for overcoming adhesion of the valve body to the seat is significantly smaller than a torque generatable by an operator. Such valves are used for example for piping of laboratory instruments, such as chromatographs, volume dosing devices for liquid medical substances in a pharmaceutical industry.
Motorized valves with turnable valve bodies are used for this reason in industrial equipment and in devices for scientific research, such as in motor driven valves of the firm “SAMSON”, Germany, model types 3241-4, type V2001-E1, type V2001-E3, type 3222/5825, type 3213/5825, type 3260/3374, type 3241-4 and model DAN 1.SN of the firm “JOVENTA” Austria.
These valves are provided with “classic” direct current or alternating current electric motors. It is therefore necessary to introduce multi-stage reducers between the outlet shafts of the motors and the rods of the turnable valve bodies of the valves, in order to increase the speed of rotation to several revolutions per minute and to increase the starting torques to the level which is sufficient for overcoming the adhesion of the valve body relative to the seat, which is especially pronounced for spherical valves even when they are used in low-pressure pipelines. Moreover, the braking of the block “classic electric motor-multi-stage reducer” with fixation of the output shaft of the reducer and of the turnable valve body of the valve connected to it, is a substantially complicated technical problem.
Correspondingly, in order to switch the turnable valve bodies of the valves with the electric motors from the position “open” to the position “closed” or vice versa, frequently the required time is from a few tenths of seconds to several minutes. This is acceptable if the motorized valve with the turnable valve body is located on the oil or gas pipeline. However, it is not acceptable when the valve must provide a cutoff of a raw material supply, for example ethylene into an explosion-prone apparatus for synthesis of polyethylene at a high pressure about 250 KPa.
Furthermore, the block “classic electric motor-multi-stage reducer” even, if it has a significant frictional interaction between kinematic links of the reducer, can not provide by itself the accuracy of angular positioning of the valve bodies less than 3°. Therefore, the valve devices are usually provided with complicated and expensive control means. In the example of the German firm, SIEMENS, device SIPART PS2, a “smart” drive, is provided for positioning of reciprocatingly movable slides or turnable valve bodies identified as an intelligent positioner for linear and rotary valves, double and single-acting actuators.
A motorized valve with a turnable valve body, which is the closest to the proposed new valve, is known from the information of the Korean firm “Daehan Control Tech Co., Ltd.” This valve operates as a cutoff valve on pipelines with high pressure, and belongs to the SMART VALVE POSITIONER SSL & SSR Series. It includes a housing with at least one inlet and at least one outlet pipe(s) for connection to a pipeline system, an axis-symmetrical seat, which is fixedly arranged inside the housing, a turnable valve body, which sits on the seat and is provided with a rod for connection to an output shaft of a rotary drive, and the rotary drive for the valve body, based on a pneumatic motor, provided with means for connection to a control system.
The output shaft of a rotor of the pneumatic motor is connected kinematically with the valve body of the valve through a cumbersome multi-stage reducer, since the torque generated by pneumatic motors can be regulated by changing a pressure of a fresh working body only within narrow limits. The pipeline for feeding the pneumatic motor with compressed air is provided with a piezoelectric valve/cutoff. The control system for the motor-powered valve is provided with a sensor of angular position of the valve body relative to the seat.
Therefore, the introduction of the cumbersome multi-stage mechanical transmission between the output shaft of the pneumatic motor and the rod of the valve body significantly increases the mass and size of the motorized valve, increases the time of triggering which usually exceeds 10 seconds, and, due to inevitable gaps, does not allow one to position the turnable valve body relative to the saddle with an angular accuracy less than 1°.